The invention discloses a leakage-proof paper diaper. The leakage-proof paper diaper comprises a body with the arc-shaped bottom, a heat preservation pad and separation edges, wherein the heat preservation pad made of cashmere is arranged at the front end of the body and is connected with the body by means of sewing, and the separation edges are arranged on two sides of the body respectively. A quadrilateral extendable piece is arranged on each separation edge, more than one air hole is formed in the bottom of the body, the body internally comprises an absorbing layer and an elastic layer, and two layers of wing-shaped cotton pieces are arranged in the elastic layer and are interlaced mutually. The leakage-proof paper diaper which is arranged integrally is good in leakage-proof effect, capable of preserving heat and comfortable to wear.